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260 

WWUS20 KWNS 270035

SEL1

SPC WW 270035

MNZ000-NDZ000-SDZ000-270800-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 691

NWS STORM PREDICTION CENTER NORMAN OK

735 PM CDT TUE JUL 26 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       WEST-CENTRAL MINNESOTA

       SOUTHEAST NORTH DAKOTA

       NORTHEAST SOUTH DAKOTA



EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 735 PM

UNTIL 300 AM CDT.



TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 75 STATUTE

MILES EAST AND WEST OF A LINE FROM 30 MILES SOUTHEAST OF

WATERTOWN SOUTH DAKOTA TO 85 MILES NORTHWEST OF ALEXANDRIA

MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).



REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH

AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR

THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS

AND POSSIBLE WARNINGS.



OTHER WATCH INFORMATION...CONTINUE...WW 687...WW 688...WW

689...WW 690...



DISCUSSION...TSTMS CONTINUE TO DEVELOP THIS EVENING ALONG A COUPLE

OF W-E ORIENTED WARM FRONTAL SEGMENTS WITHIN INTENSIFYING LOW-LEVEL

WAA REGIME.  00Z ABR SOUNDING IS QUITE REPRESENTATIVE OF THE AMBIENT

ENVIRONMENT...FEATURING MLCAPE OF AROUND 3500 J/KG...45 KT OF

DEEP-LAYER SHEAR...A LOW LCL HEIGHT AND EFFECTIVE SRH OF AROUND 400

M2/S2.  AS SUCH...A RISK FOR TORNADOES WILL EXIST WITH ANY STORMS

THAT CAN REMAIN MORE DISCRETE...IN ADDITION TO LARGE HAIL AND

DAMAGING WINDS.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

550. MEAN STORM MOTION VECTOR 26020.





...MEAD

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